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48 The Dairyman DECEMBER 2009
NUTRITION
Summer feeding strategies for your herd
MILK yields often fall
rapidly during the sum-
mer months as pasture
quality and in some cases quan-
tities decline. They may also be
influenced by rising endophyte
and sporedesmin levels particu-
larly in ryegrass dominant pas-
tures.
These changes in feed compo-
sition and supply also coincide
with dairy farms' animal breed-
ing programmes, so can impact
on cow condition and the pro-
portions of cows in calf.
Options for tackling these
issues depend on location of
farms and therefore climatic
aspects, soil types, pastures or
crops, the farming system and
whether irrigation is available.
Therefore, dairy farmers need to
review historical herd
performances, climatic charac-
teristics, feeding and mating
management and feed to identi-
fy their best options.
Understanding key principles
should be part of this exercise.
It is important when review-
ing empty rates to identify
whether particular age groups
are disproportionately repre-
sented in the empty cow group,
such as first calvers. If this is
the case, then the heifer rearing
regime needs to be reviewed to
ensure that heifers attain target
body weights at mating and
calving, and in good condition.
Underweight heifers at calv-
ing will never milk to their
potential as they will continue to
grow over several lactations.
They are also likely to compete
less well against their larger,
older herd mates. Many of these
cows have not received any min-
eral supplementation, so key
trace minerals associated with
health and fertility may be sub-
optimal.
Timing of breeding issues is
important as it may indicate
potential problems and possible
solutions. For example cows
not cycling early enough may
have calved down in poor condi-
tion, had difficulty calving, suf-
fered metabolic problems or
may be losing too much condi-
tion.
Drying off, dry cow, transition
cow and early lactation feeding
and management strategies
should then be reviewed, as well
as potential underlying health
issues. Offering high energy
feed supplements may help
address some of these issues.
Recording the proportion of
early (3-4 weeks) and late
returns should also be consid-
ered, as the former group proba-
bly never conceived while the
most in the latter group probably
failed to hold their pregnancies.
Higher genetic merit cows
have been selected to prioritise
more of their resources to pro-
ducing milk relative to gaining
condition, resulting in delays in
starting to cycle if nutrient
intakes are limited.
Therefore, it is important not
to make major changes in
feeding and management over
and just after the animal breed-
ing programme, especially as
this is when the greatest changes
in pasture quality tend to occur.
The benefits of supplementa-
tion during this period, whether
as conserved forages, crops or
bought-in feeds should be meas-
ured, taking account of improve-
ments in fertility not just pro-
duction.
Rapid declines in milk pro-
duction are often combined with
falling milk protein to fat ratios,
both of which point to inade-
quate nutrient intakes. If these
patterns are evident across
years, then it would be worth
reviewing feeding and manage-
ment options to address this, to
improve overall milk yields and
fertility rates.
The key to success is attention
to detail, effective management
of any farming system, and
sound nutritional advice.
By Dr Julian
Waters
Nutrition consultant
New Zealand owned and operated since 1915.
Performance Nutrition
BIO-SIL®
Nutritech Silage Inoculant
Customer service
0800 736 339
Available in granular
and water soluble formulations.
www.nutritech.co.nz